unique typo

laravel/database/schema/grammars/mysql.php

@@ -260,7 +260,7 @@ class MySQL extends Grammar {
 	}
 
 	/**
-	 * Generate the SQL statement for a drop unqique key command.
+	 * Generate the SQL statement for a drop unique key command.
 	 *
 	 * @param  Table    $table
 	 * @param  Fluent   $command